Clarify addResources parameter description

This commit clarifies the role of the 'addResources' flag and makes
it explicit that any duplicate found in the target directory are
actually removed

Fixes gh-1479

spring-boot-tools/spring-boot-maven-plugin/src/main/java/org/springframework/boot/maven/RunMojo.java

@@ -64,11 +64,9 @@ public class RunMojo extends AbstractDependencyFilterMojo {
 	private MavenProject project;
 
 	/**
-	 * Add maven resources to the classpath directly, this allows live in-place editing or
+	 * Add maven resources to the classpath directly, this allows live in-place editing of
-	 * resources. Since resources will be added directly, and via the target/classes
+	 * resources. Duplicate resources are removed from {@code target/classes} to prevent
-	 * folder they will appear twice if {@code ClassLoader.getResources()} is called. In
+	 * them to appear twice if {@code ClassLoader.getResources()} is called.
-	 * practice, however, most applications call {@code ClassLoader.getResource()} which
-	 * will always return the first resource.
 	 * @since 1.0
 	 */
 	@Parameter(property = "run.addResources", defaultValue = "true")

spring-boot-tools/spring-boot-maven-plugin/src/site/apt/usage.apt.vm

@@ -104,11 +104,11 @@ mvn spring-boot:run
   {{{./examples/run-debug.html}Debug the application}} for more details.
 
   By default, any <<src/main/resources>> folder will be added to the application classpath
-  when you run the application. This allows hot refreshing of resources which can be very
+  when you run the application and any duplicate found in <<target/classes>> will be
-  useful when developing web applications. For example, you can work on HTML, CSS or JavaScipt
+  removed. This allows hot refreshing of resources which can be very  useful when developing
-  files and see your changes immediately without recompiling your application. It is also a
+  web applications. For example, you can work on HTML, CSS or JavaScipt files and see your
-  helpful way of allowing your front end developers to work without needing to download and
+  changes immediately without recompiling your application. It is also a helpful way of
-  install a Java IDE.
+  allowing your front end developers to work without needing to download and install a Java IDE.
 
   Of course, if your resources are using tokens that are filtered by Maven, you may want
   to disable that feature as follows: